Common themes across all segments of electronic packaging today are density and performance. High density interconnect (HDI) technology is one of the most commonly utilized methods for electronic package density improvement, while many different areas have been investigated for performance improvement, from low loss dielectric and conductor materials, to via design and via stub reduction. Electrical performance and density requirements are sometimes complementary, but often times, conflicting with one another.
This paper will describe the design, materials, fabrication, and reliability of a new Z-Interconnect technology that addresses both high density and high performance demands simultaneously. Z-Interconnect technology uses an electrically conductive adhesive to electrically interconnect several cores (Full Z) or sub-composites (Sub Z) in a single lamination process. Z-Interconnect technology will be compared and contrasted to other commonly used solutions to the performance and density challenges. HDI or sequential build-up technology is a pervasive solution to the density demands in semiconductor packaging and consumer electronics (e.g. Smart phones), but has not caught hold in HPC or A&D printed wiring board (PWB) applications. One solution for PWB electrical performance enhancement is plated through hole (PTH) stub reduction by “back drilling” the unwanted portion of the PTH.
Pb-free reflow and Current Induced Thermal Cycling (CITC) test results of product coupons and specially designed test vehicles, having component pitches down to 0.4mm, will be presented. Z-Interconnect test vehicles have survived 6X Pb-free (260C) reflow cycles, followed by greater than 3000 cycles of 23C–150C CITC cycles. Test vehicle and product coupons also easily survive 10 or more 23C–260C CITC cycles.
Materials for High-Density Electronic Packaging and Interconnection